Advances in Materials Manufacturing Science and Technology II

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Authors: Mei Ling Fung, Kai Ming Yu, Man Wah Yuen
Abstract: Nowadays’ optical frames are the result of a collaboration between designers and engineers; it is a combination of high technology and art. Around 250 technical operations are performed in order to make a high-quality metal frame, and there are 120 to 180 operations to make a plastic frame. Although the Asian manufacturers of optical frames are prevailing in the world market, a relatively rudimentary trial-and-error method is being used. A more systematic and analytic approach is thus needed for them to grasp the evolution trends in the competitive market. This paper discusses how Gabriel Tarde’s diffusion S-curve and the TRIZ theory can be employed to analyze the evolution trends in optical frame design and manufacturing.
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Authors: Shan Li, Ding Hua Zhang, Jing Tao Zhou, Guang Hui Ma, Hai Yang
Abstract: Nowadays, most data in enterprise systems is still stored in relational databases, which brings the majority of difficulties to achieve information interoperation between enterprise-level heterogeneous systems. In this context, we propose a middleware to integrate information from heterogeneous enterprise system based on XML standard. The proposed integration architecture aims at providing a coherent and meaningful view of the integrated heterogeneous information systems by leverage the back-end relational data sources. The architecture of the middleware relies on the well-known mediator/wrapper architecture and satisfies the semantic integration features by several main functions including data descriptions, schema transformations and integrations based on the XML-Schema standard.
516
Authors: Kin Man Au, Kai Ming Yu
Abstract: The cooling system of a plastic injection mould is important as it affects the quality and productivity of the polymeric components or assemblies. Contemporary cooling channel design is confined to simple configurations of straight-drilled coolant passageway around the mould insert. Undesirable defects resulted during injection moulding, such as warpage, are inevitable. The application of rapid tool (RT) based on solid freeform fabrication (SFF) technologies with conformal cooling channel (CCC) design has provided a profound opportunity in quality improvement of polymeric components. In this study, a novel design of variable radius conformal cooling channel (VRCCC) is proposed to achieve better uniform cooling performance. Thermal-FEA and melt flow analysis are used to validate the method.
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Authors: Shen Dong, Xiao Li Zhao, Jing He Wang, Zheng Qiang Li, Tao Sun, Ying Chun Liang
Abstract: Here a simple and direct method based on transfer printing has beep developed, in which rigid stamps transfer metal films deposited on the relief surface of the stamps onto patterned organic substrates. Ultra-precision machining technology is combined with conventional photolithography to fabricate patterned Si stamps and organic substrates by replica molding. Experiment results indicate that patterned metal films on Silicon stamps were successfully transferred onto PDMS substrates. Fabrication of patterned metal films on organic substrates by transfer printing may suit for fabricating sub-micrometer and nanometer scale features in a single process.
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Authors: Bang Yan Ye, Bo Wu, Jian Ping Liu, Xiao Chu Liu, Xue Zhi Zhao
Abstract: Theoretical analysis and experiments on bearing race show that a suitable residual compressive stress on roll path of bearing race can prolong its contact fatigue life. However, residual tensile stress is often found on workpiece surface of bearing race. To actively control the residual stress state and improve fatigue life of bearing part, a new method of pre-stress hard cutting is applied. In this paper, the principle of pre-stress hard cutting for bearing race is introduced as well as the experiments on it. In the experiments, residual stress, hardness and roughness of machined surface are measured and analyzed. Moreover, micro-topography and texture characteristics of machined surface are investigated and experimental results are compared with that by grinding. It is found that we can get residual compressive stress and fine quality on machined surface of bearing race by pre-stress hard cutting and increase its productivity as well.
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Authors: Yan Yan Yan, Bo Zhao, Yan Wu, Chuan Shao Liu, Xun Sheng Zhu
Abstract: In the paper, the machining characteristics of two dimensional ultrasonic grinding(TDUG) are analyzed, and based on the analysis of the working locus of abrasive particle under TDUG and mechanical performances of fine-crystalline ZrO2 ceramics, a theoretical model of material removal rateMRRis proposed under TDUG with workpiece adhered to ultrasonic vibration respectively from the orthogonal directions. The model shows that any increase of static load, size of grain, work speed, number of effective dynamic abrasive particle, the amplitude and frequency of tool or any decrease of fracture toughness property and hardness will result in the increase of the MRR, and the theoretical model of the MRR is tested, meanwhile the paper draws the conclusion that the surface quality under TDUG is superior to that under common grinding, which is tested by the means of grinding of fine-crystalline ZrO2 ceramics.
532
Authors: Wen Jun Deng, Yong Tang, Wei Xia, Zhen Ping Wan
Abstract: A coupled thermal-mechanical model of plane-strain orthogonal metal cutting with continuous chip formation is developed to investigate the residual stresses in the finished workpiece. Deformation of the workpiece material is treated as elastic-viscoplastic with isotropic strain hardening, and the numerical solution accounts for coupling between plastic deformation and the temperature field, including treatment of temperature-dependent material properties. Automatic continuous remeshing and adaptive meshing technique are employed to achieve chip separation at the tool tip region and a satisfactory solution. The finite element model is well validated by comparing values of the predicted cutting forces and residual stresses with experimental results. Based on the established finite element model, the effect of rounded cutting edge radius on residual stress distribution is analyzed. The results show that altered cutting edge radius clearly produced significant changes in residual stresses. The maximum tensile residual stress and its penetration depth decrease as the cutting edge radius increases.
536
Authors: Lu Lu Jing, Gang Liu, Ming Chen
Abstract: In die and mold industry, there is a tendency to use milling in the finishing machining of dies and molds as an alternative to the traditional EDM process, consequently the surface integrity in milling is considered as one of the most important indices. In this study, surface roughness, micrograph of machined surface, surface microhardness, residual stress, and metallurgical texture of the surface layer were considered. The influence of geometrical characteristics of cutting tools and tool wear on surface integrity was studied. The results showed that hard milling of hardened die steel could yield a quite satisfied surface integrity by proper process; compressive residual stress was induced on machined surface, and the compressive stress induced in transversal direction was almost 3 times of that in longitudinal direction; tool wear had a significant negative influence on surface finish and caused the machined surface soften. These conclusions revealed the effects of tool conditions on surface integrity and would play a practical significance in the machining of hardened die steel.
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Authors: Shirakashi Takahiro, Watanabe Ryo
Abstract: The effect of cutting fluids on surface characteristics of glassone of homogenuious brittle materialsare discussed. In water both fracture stress and tough ness are greatly decreased and many uncontrollable cracks are easily generated and propagate in maching.The other hand, in spindle oil, both the stress and toughness becomes lager, and the crack generation and propagation also restrained than those in water. In order to obtain the defect free surface of glass by machining, both the generation of cracks and propagation should be controlled or restrained. Since they are greatly affected by the surface and/or at the crack tip energy of glass, some methods for increasing the energy are proposed.
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Authors: Yao Chen, Ai Bing Yu, Da Wei Jia, Nan Zhao
Abstract: Data envelopment analysis (DEA) evaluation system of metal materials was established. Evaluated metal materials were regarded as decision making units (DMUs). Property parameters of metal materials were selected as inputs of DMUs, and machining process parameters were selected as outputs of DMUs. Input and output data sequences could be obtained through data processing operations. Mathematics programming model was founded and optimal values of all the evaluated materials were calculated based on the model. Machinabilities of metal materials could be evaluated by comparing the optimal values. Taken 1Cr18Ni9Ti, GCr15, Q235, 45# and LY11 for example, machinabilities of five metal materials were ranked. Research results suggest that DEA method can synthetically consider the relationship between property parameters and machining process parameters. DEA is proved to be a reasonable and available method to evaluate metal material machinability.
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